.then((connection: Connection) => {
     self._connection = connection;
     return connection.createChannel();
 })

 /**
  * Close the connection cleanly. Will immediately invalidate any unresolved operations, so it's best to make sure
  * you've done everything you need to before calling this. Will be resolved once the connection, and underlying
  * socket, are closed.
  *
  * @returns Rx.Observable<void>
  */
 public close(): Rx.Observable<void> {
   return Rx.Observable.fromPromise(this.connection.close());
 }

 const connectionDisposer = Rx.Disposable.create(() => conn.close().catch(err => Rx.Observable.throw(err)));

 /**
  * Opens a channel. May fail if there are no more channels available.
  *
  * @returns {any}
  */
 public createChannel(): Rx.Observable<RxChannel> {
   return Rx.Observable.fromPromise(this.connection.createChannel())
     .map((channel: Channel) => new RxChannel(channel));
 }